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Because PDK: Some observations after a roll race

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Old 03-11-2018, 12:57 PM
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robmypro
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Default Because PDK: Some observations after a roll race

Note: This is going to be a controversial topic. Please don't shoot the messenger.

A buddy of mine has a pretty well modded GT4. He has Dundon headers (he says they make power!), a tune, an IPD Plenum/GT3 Throttle Body, and maybe some other parts. His GT4 is really nice. Anyways, we get gas on the way to Cars and Coffee and shortly thereafter find ourselves with a very nice open stretch of road. We were probably going 55 to 65 mph, when we jump on it. My .1 GT3 pulls away pretty steadily. I would say a good 1/4 to 1/2 car length immediately opens up, and then it continues to widen. We did it a couple of times, and each time the result was the same. No big deal, as this is a GT3 vs GT4, although a seriously modded GT4.

When we get to C&C he tells me that he did a similar roll race against a friend in his new .2 Manual GT3. Those races resulted in a dead heat, with the GT3 starting to pull away at ridiculous speeds. We have a pretty good group of GT car owners, so this was a bit of a surprise. I guess we were thinking my .1 GT3 would possibly stay even with the GT4, but instead mine just walked away.

I think the reason is pretty clear. The difference is the PDK, with its fast shifts and extra gear/lower final drive versus the 6 speed manual. We could see a noticeable gap open every time the GT4 shifted. Subtle, but maybe a 1/4 car length jump each time. But the GT3 was pulling away each time from the start. The GT4 was quick, though. Those mods made a huge difference, and i am really impressed.

We will try to line up a .1 PDK vs .2 manual at Bandimere so we can see what the rest of the data looks like, but as of right now our assumption will be that 0-60 and 1/4 mile will favor the .1 PDK equipped GT3 over the .2 MT GT3. The .2 PDK should show an even bigger gap.

Btw, we also did a roll race with my .1 GT3 vs a .1 RS. It was essentially dead even. The RS was very low on fuel, while mine had a full tank. No passengers in either car. I think the GT3 would start to pull away at higher speeds due to less aero. That result wasn’t super surprising, but it was a data point.

At some point I am going to get headers. We’ll try to get the GT4, GT3 RS, and both GT3’s at the track to see how they compare, then do headers and try it again. My assumption is that with headers the .1 GT3 should be very competitive with the .2 PDK. But we’ll see.

Next time we will get video. Sorry, this was not planned. We just had a huge open stretch, no cars around, and well...you know.




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Old 03-11-2018, 07:33 PM
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fskof
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I would love to see the results of a 991.1 pdk vs 991.2 pdk vs 991.2 manual test. It’s probably only a matter of time before a video appears on YouTube
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Old 03-11-2018, 08:55 PM
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Sorry, your buddy needs to learn how to 'shift'... here's my .2 GT3 6spd vs. a new '18 Turbo S.. from a roll... no way a GT4 plays with this crowd from a roll:


Best Regards,
Dave
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Old 03-11-2018, 09:16 PM
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Originally Posted by robmypro View Post
So my buddy did a roll race against a MT .2 GT3 with his GT4. This is not a stock GT4, as it has Dundon headers and a tune. In his words, the GT3 had him by maybe a “splitter’s width.” Essentially it was dead even up until stupid speeds, at which point the .2 MT GT3 started to pull away. Needless to say all parties involved were pretty surprised at the GT4, with minor mods. So anybody wondering if Dundon headers and tune make serious power or not, there you go. They do.
If this is the same GT4 that was discussed in the GT4 sub-forum, it has more than just headers and tune...

Originally Posted by SCCAForums View Post
Sorry, your buddy needs to learn how to 'shift'... here's my .2 GT3 6spd vs. a new '18 Turbo S.. from a roll... no way a GT4 plays with this crowd
if from the same thread, the GT3 driver's credentials are pretty substantive. The GT4 is lighter, and in this case, with more power, so it's not surprising to me that it is close.
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Old 03-11-2018, 09:16 PM
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PDK only makes a huge difference if you don’t know how to operate the stick. 1:24.95s manual vs 1:24.66s PDK lap time in this test difference of less than 0.29 seconds: http://www.motortrend.com/cars/porsc...t-test-review/
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Old 03-11-2018, 09:17 PM
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Nicely done........
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Old 03-11-2018, 09:26 PM
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Originally Posted by Dewinator View Post
PDK only makes a huge difference if you don’t know how to operate the stick. 1:24.95s manual vs 1:24.66s PDK lap time in this test difference of less than 0.29 seconds: http://www.motortrend.com/cars/porsc...t-test-review/

That is a speed track layout. Do it on another, different track and the results might not be that close. Also RP might have been speed shifting which most normal drivers don't.
Not only that but this impromptu test was don't altitude which the MT test wasn't.
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Old 03-11-2018, 09:36 PM
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I am the Stig and can switch gears faster than PDK.....LOL
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Old 03-11-2018, 09:37 PM
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“Don’t altitude” or not, I think it’s awesome how when you get an MT car you suck at it at first and learn to get better and better, eventually getting within a spitting distance of just having the computer drive for you once you’ve really mastered the car.
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Old 03-11-2018, 09:39 PM
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Originally Posted by Psup4s View Post
I am the Stig and can switch gears faster than PDK.....LOL
Lol SOME SAY his daily driver is a double-clutched manual with FOUR PEDALS.
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Old 03-11-2018, 09:47 PM
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Originally Posted by fskof View Post
I would love to see the results of a 991.1 pdk vs 991.2 pdk vs 991.2 manual test. It’s probably only a matter of time before a video appears on YouTube
We will definitely try to get the cars together at Bandimere to get really good data.

Originally Posted by SCCAForums View Post
Sorry, your buddy needs to learn how to 'shift'... here's my .2 GT3 6spd vs. a new '18 Turbo S.. from a roll... no way a GT4 plays with this crowd from a roll:

https://youtu.be/2nlH8qkgMtw

Best Regards,
Dave
As i said, the GT4 wasn’t stock. But the key info here is modded GT4 races .2 GT3 MT and it is a dead heat. My .1 GT3 walked away from GT4 under similar conditions. And both guys know how the shift and have tons of track time. So no need to insult anyone.

Originally Posted by chillindrdude View Post
If this is the same GT4 that was discussed in the GT4 sub-forum, it has more than just headers and tune...

if from the same thread, the GT3 driver's credentials are pretty substantive. The GT4 is lighter, and in this case, with more power, so it's not surprising to me that it is close.
I think power to weight is pretty close with the .2 GT3 and modded GT4. So not sure that result was surprising. My .1 GT3 walking away from the GT4 was. And again, both drivers know what they are doing.

Originally Posted by Dewinator View Post
PDK only makes a huge difference if you don’t know how to operate the stick. 1:24.95s manual vs 1:24.66s PDK lap time in this test difference of less than 0.29 seconds: http://www.motortrend.com/cars/porsc...t-test-review/

Even from the jump my GT3 pulled away, so no shifting was even involved for the first 1/2 car length. Again, both guys know how to drive. My take is the gearing of the PDK (and 7 gears to 6) was the real difference here. I was probably in a lower gear ratio at every speed. Again, i don’t think these findings are controversial. Ultimately, a .1 GT3 with PDK is going to walk away from the .2 GT3 with manual on track or on the street. The extra 25 HP from the .2 and improved torque curve will not be enough to mitigate the PDK with better gearing. But we will try to get all these cars on the dragstrip to put real meat to it.

Originally Posted by abiazis View Post
Nicely done........
Thanks! It was fun.

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Old 03-11-2018, 10:14 PM
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Also, Motor Trend tested the .1 GT3 and got a 0-60 time of 3.1 seconds. The .2 manual GT3 is rated at 3.5 seconds 0-60. Why would this be surprising that the .1 GT3 is faster than the manual .2?
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Old 03-11-2018, 10:21 PM
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Originally Posted by robmypro View Post
Also, Motor Trend tested the .1 GT3 and got a 0-60 time of 3.1 seconds. The .2 manual GT3 is rated at 3.5 seconds 0-60. Why would this be surprising that the .1 GT3 is faster than the manual .2?
There are a few things mixed up here:
  • US mags test 0-60 from a small roll
  • You are comparing tested Vs. rated
  • 0-60 performance for PDK is mostly about the launch, which is not relevant from a roll
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Old 03-11-2018, 10:25 PM
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Originally Posted by Bardman View Post


There are a few things mixed up here:
  • US mags test 0-60 from a small roll
  • You are comparing tested Vs. rated
  • 0-60 performance for PDK is mostly about the launch, which is not relevant from a roll
If we talk about rated, both are rated at 3.5 seconds 0-60. So you would not expect the .2 manual to be quicker. Also, 7 gears to 6 shoukd be an advantage. And finally, we are not talking about “on paper.” These are actual results. Don’t shoot the messenger!
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Old 03-11-2018, 10:26 PM
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Originally Posted by robmypro View Post
Ultimately, a .1 GT3 with PDK is going to walk away from the .2 GT3 with manual on track or on the street. The extra 25 HP from the .2 and improved torque curve will not be enough to mitigate the PDK with better gearing.
I think time will prove that statement quite inaccurate, and quite a stretch from thin data. Porsche quotes identical 100-200 kph times for the PDK and manual in the .2, and they state they are very even in their own roll-on testing. Either Porsche’s times are incorrect or the .1’s going to get dropped from a roll through that speed range.

Keep in mind that in addition to the 25 hp the .2 manual gets a weight advantage and lower frictional losses through the gearbox. That’s a 5.3% power advantage, 1.2% weight advantage and ~1% more power making it to the ground due too lower driveline losses. The latter two are likely what allow the manual to run with the PDK from a roll in Porsche’s testing despite both the slower shifting and gearing disadvantage. I suspect as we get more broken in cars into owners hands we’ll get plenty of .1 vs .2 runs to compare that will disprove your assertion above. The .1 will pull on the launch due to launch control, but how often are you launching?
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